I disagree. Mary is not taking a vow of chastity. She is expressing confusion as to how she could conceive while being a virgin.
“How will this be,” Mary asked the angel, “since I am a virgin?” Luke 1:34
And then in Matthew 1:25 we read, " But he did not consummate their marriage until she gave birth to a son. And he gave him the name Jesus."
It doesn't say they never consummated their marriage or that Mary remained a virgin. It says they didn't consummate their marriage until after the birth of Jesus. At the end of the day, it's just an interesting discussion point anyway. It really doesn't matter one way or the other.